As a conventional stator, there has been provided a stator in which an interphase insulating paper for fulfilling insulation between windings of the concentrated-winding coil is folded back in a V-like shape by a folding line that is a straight line extending along the axial direction, the insulating paper then being inserted between the windings of the coil so that the folding line is positioned radially inside of the stator see, e.g., JP 2013-118717 A).